wasi-shims: the parking kernel — real pollables, poll, timers, always on (A5) - #71
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…n (A5) Track 2, scoped to the known consumer (polymorph-iroh's upstream-iroh class: unmodified iroh/tokio parking its reactor in wasi:io/poll with timer + socket pollables). What that consumer needs, and what ships: - Pollable over host-supplied readiness: publicly constructible (new Pollable(ready, wait)) — the interop seam for external providers (the consumer's sockets glue, deliberately outside this package, mints pollables the kernel polls uniformly; wait() follows the promise-swap producer shape, spurious wakes fine). @suspending block() with a sync fast path; Pollable.timer(deadline, now) armed lazily on first wait, readiness by clock so the wake is exact. - poll(): sync fast path (indices return without a suspension when anything is ready — the per-declaration granularity A1 was designed for, vs jco's transpile-time asyncWasiImports), race-and-recheck park otherwise, unbranded throw on the empty list (io.wit's trap). - monotonic-clock@0.2 subscribe-instant/duration mint real timers — the always-ready timer stub was the livelock half for a sleeping reactor. - Streams stay buffer-backed (known consumers do no stream I/O; bytes ride datagrams). ALWAYS ON, not an opt-in profile (operator ruling): the A1/A2 machinery provides the optionality at the right layer already. On engines without JSPI, chooseMode degrades to plain and everything behaves like the old stubs until a guest genuinely parks — which then raises a clean NeedsJspi at the park site instead of livelocking; jspi:false is the per-instantiation opt-out. The retired framing ("three tiers", "never (c) in this package") is superseded by embedder-api.md amendment A5; intrinsics.md records the narrowed zero-cost pin (sync-only AND no marked providers). Pins: - tests/blocking_test.ts (kernel): default-ready sync block; timer parks ~60ms and flips ready; externally-woken promise-swap pollable; poll fast path returns synchronously; poll parks and wakes with the ready index; empty-list trap. - tests/blocking_guest_test.ts + testdata/blocking-guest.wat (through a REAL guest frame; the fixture shares the pollable resource type across the two imported instances via an outer alias, like real wasip2 components): pollable.block (an A2-marked resource method) parks the frame for the full 80ms — FAIL-ON-PRE-FIX: the old stubs returned in ~0ms; poll parks, wakes, and lowers its ready list through guest realloc at resume time; jspi:false refuses the park cleanly. Gates: test-wasi-shims 50/0 (incl. the iroh exec-model integration, green under the always-on kernel at unchanged runtime), test-ct-runner, test-ports, websocket-conformance 55/55 at unchanged wall time (14.4s vs 14.5s baseline — the mode flip is timing-invisible for the callback-ABI consumers), smoke-tls suites PASS. iroh-exam is environmentally broken on this machine independent of this diff: the consumer checkout's prebuilt endpoint artifact is stale against its own moved WIT surface and the redirected rebuild fails at `cargo --locked` before any deltic code runs (consumer tree needs an operator pull/rebuild; tree verified clean before/after).
lann
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Aug 11, 2026
findings: IROH-2 — polymorph-iroh's redundant tier-(c) overrides post-#71 (DRAFT)
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Track 2, scoped per operator direction to what the known consumer needs (polymorph-iroh's upstream-iroh class: iroh/tokio parking its reactor in
wasi:io/poll).Ships: publicly-constructible
Pollable(ready, wait)(the interop seam for consumer-side sockets glue; promise-swap wake contract),@suspending block()andpoll()with sync fast paths (per-declaration granularity — the A1 design payoff vs jco's transpile-time flag), realPollable.timerbehind monotonic-clocksubscribe-*(the always-ready timer stub was the livelock half), empty-list trap per io.wit. Streams stay buffer-backed (known consumers do no stream I/O).Always on, not opt-in (operator ruling):
chooseModealready degrades to plain on non-JSPI engines — old-stub behavior until a guest genuinely parks, then a cleanNeedsJspiinstead of a livelock;jspi: falseis the per-instantiation opt-out. Contract A5 retires the three-tier framing and the 'never (c) in this package' mission line; intrinsics.md records the narrowed zero-cost pin (sync-only AND no marked providers).Pins: kernel unit suite + a hand-written genuinely-blocking guest (
blocking-guest.wat, cross-instance resource type via outer alias) —blockparks a real frame for the full 80ms (fail-on-pre-fix: old stubs returned in ~0ms),pollparks/wakes and lowers its ready list through guest realloc at resume,jspi:falserefuses cleanly.Gates: test-wasi-shims 50/0 (incl. iroh exec-model integration, unchanged runtime), ct-runner, ports, websocket-conformance 55/55 at unchanged wall time (14.4s vs 14.5s baseline), smoke-tls PASS. iroh-exam is environmentally broken on this machine independent of this diff (consumer checkout's prebuilt artifact stale vs its own moved WIT; redirected rebuild dies at
cargo --lockedbefore any deltic code runs) — needs an operator pull/rebuild of~/p/polymorph/polymorph-iroh.